1. Field of the Invention
The present invention relates to an information processing apparatus for searching for a desired image processing apparatus connected to a network, such as a printer, a method for controlling the information processing apparatus, and a storage medium.
2. Description of the Related Art
In recent years, network technology has been significantly improved in accordance with the widespread use of large-scale networks, such as the Internet. Additionally, a technology known as “Web service” has become widely known in which a variety of network services are provided by cooperation among devices connected via a network using Web related technologies, such as the extended markup language (XML) and the simple object access protocol (SOAP). Among these services, a service known as a print service is provided which receives a print request from a station connected to the network via the network, registers or searches a plurality of printing devices, and causes a printing device having a user's desired function to carry out a print operation.
A device for providing such a print service, namely, a printing device can notify a station in the network of its own device information. Examples of the device information include information associated with the performance of the printing device (e.g., paper size, monochrome/color printing, print output attributes including output resolution, and finishing capability including sorting and stapling) and information associated with the physical location where the printing device is installed (e.g., room A in building AA). By acquiring the device information or searching for the device information, the station in the network can select a printing device having the desired device information from among a plurality of printing devices.
A typical manner in which the station searches for a desired printing device is now herein described. A station attempting to use a service transmits a service search request to the network using a multicast packet of a user datagram protocol (UDP). Since the service search request utilizes a multicast packet, the service search request is transmitted to a plurality of printing devices in the network.
The service search request contains a search condition describing printing device information for a service that the station (i.e., a user) desires. The printing device receives the service search request and determines whether its own device information satisfies the device information of the search condition contained in the service search request.
If the printing device can provide the service that the station (user) which transmitted the service search request desires, that is, if its own device information satisfies the search condition, the printing device sends a reply to the station which transmitted the service search request. In contrast, if the printing device cannot provide the service, that is, if its own device information does not satisfy the search condition, the printing device sends no reply to the station. The reply to the service search request contains a uniform resource locator (URL) indicating the location of the printing device and the device information about the printing device. Upon receiving the reply to the service search request, the station is informed of the presence of a printing device that can provide the desired service.
However, when the station searches for the desired printing device using this method, a multicast packet using the UDP protocol is used. Accordingly, the size of the service search request is limited to the transmittable size defined for the multicast packet of the UDP protocol. That is, if a search condition in the service search request contains a large number of device information pieces, the multicast packet may not be able to handle such a large amount of specified device information. For example, if an amount of data exceeds 1428 bytes, which is a maximum transmittable data size defined for a multicast packet according to the UDP protocol, the service search request cannot be transmitted to the network. As a result, the desired printing device cannot be searched for.
In an effort to overcome the aforementioned disadvantage inherent to the multicast features of the UDP protocol, another search method has been proposed by Japanese Patent Laid-Open No. 8-328781. Here, instead of transmitting a service search request containing a search expression to a network, a searching device for searching for a service requests device information from all printing devices connected to the network. Subsequently, the searching device receives device information from each of the printing devices. The searching device then displays a list including the name of the printing devices and their device information. A user then selects one of the printing devices displayed and, as a result, the selected device is designated as the device to be used.
However, in the above-described known method, if a large number of devices exist in the network and all of the devices transmit their own device information to the station, the network traffic increases. In addition, the user needs to search for a printing device having the desired attributes from the displayed list. That is, information about devices that are not necessary for the user is unnecessarily displayed in the list.